Si-containing thin films are used widely in the semiconductor, photovoltaic, LCD-TFT, flat panel type devices, refractory materials, or aeronautics industries. Si-containing thin films may be used for example, as dielectric materials having electrical properties which may be insulating (SiO2, SiN, SiCN, SiCOH, MSiOx). Si-containing thin films may be used as conducting films, such as metal silicides or metal silicon nitrides. Due to the strict requirements imposed by downscaling of electrical device architectures towards the nanoscale (especially below 28 nm node), increasingly fine-tuned molecular precursors are required which meet the requirements of volatility (for ALD process), lower process temperatures, reactivity with various oxidants and low film contamination, in addition to high deposition rates, conformality and consistency of films produced.
Dussarrat et al. disclose a class of Si precursors for CVD of Si-containing films having the general formula (R1R2N)xSiH4-x wherein x is between 1 and 4 and the R substituents are independently H, C1-C6 linear, branched, or cyclic carbon chains (WO2006/097525).
Hunks et al. disclose a wide range of Si-containing precursors in US2010/0164057, including silicon compounds having the formula R4-xSiLx, wherein x is an integer having a value from 1 to 3; R may be selected from H, branched and unbranched C1-C6 alkyl, C3-C8 cycloalkyl, and C6-C13 aryl groups; and L may be selected from isocyanato, methylethylketoxime, trifluoroacetate, triflate, acyloxy, β-diketiminate, β-di-iminate, amidinate, guanidinate, alkylamino, hydride, alkoxide, or format ligands. Pinnavaia et al. claim a method for the preparation of a porous synthetic, semi-crystalline hybrid organic-inorganic silicon oxide composition from silicon acetylacetonate and silicon 1,3-diketonate precursors (U.S. Pat. No. 6,465,387).
Hexacoordinate silicon containing compounds are also known in the art and have been proposed for CVD applications (see, e.g., Karsch and Segmüller, Silicon and Germanium Compounds with Amidinate Ligands, Organosilicon Chemistry V From Molecules to Materials pp. 271-276 of Organosilicon Chemistry V: From Molecules to Materials, WILEY-VCH Verlag GmbH & Co., 2003).
Despite the wide range of choices available for the deposition of Si containing films, additional precursors are continuously sought to provide device engineers the ability to tune manufacturing process requirements and achieve films with desirable electrical and physical properties.